Chicken parts. Potato cut lengthwise. Onion cut in quarters. Spread potato and onion around chicken. Put butter on chicken and potato. Sprinkle with salt, pepper and garlic powder. Pour 1/2 can tomato sauce (8 ounce) mixed with water (thin sauce) over all chicken and vegetables. Put grated cheese (Parmesan) over top. Cover with foil. Bake at 350 degrees for 1 1/2 hours. Uncover. Bake 1/2 hour.